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Examines the role of endothelium and K[sup +] channels in dobutamine-induced relaxation in rat mesenteric artery. Measurement of isometric tension in endothelium-intact and -denuded arteries; Inhibition of phenylephrine-induced sustained tension by dobutamine; Conclusion on endothelium.

An organocatalytic cascade reaction of 2-nitrocyclohexanone and α, β-unsaturated aldehydes was developed. Bicyclo[3.3.1]nonanone products were obtained with good yields and excellent enantio- selectivities. The reaction occurred with unusual regioselectivity. A dienolate-iminium activation mechanism was proposed. The products were transformed to eight-membered cyclic ketones with high enantioselectivity. [ABSTRACT FROM AUTHOR]

Baicalin purified from the root of Radix scutellariae is widely used in clinical practices. This study aimed to evaluate the effect of baicalin on the pharmacokinetics of nifedipine, a CYP3A probe substrate, in rats in vivo and in vitro. In a randomised, three-period crossover study, significant changes in the pharmacokinetics of nifedipine (2 mg/kg) were observed after treatment with a low (0.225 g/kg) or high (0.45 g/kg) dose of baicalin in rats. In the low- and high-dose groups of baicalin-treated rats, C max of total nifedipine decreased by 40%±14% (P

The interview is with Zhen-Yu Chen, who is the associate editor of "Journal of Agricultural and Food Chemistry" and on the faculty of the Chinese University of Hong Kong. The topics include the responsibilities of the journal's associate editor, travel to institutes and universities in China to research journal publishing, and the outlook for agricultural research and international cooperation among researchers.

A number of 6-aryl-5,6-dihydrophenanthridines were prepared in good yields via an intramolecular dehydrogenative coupling of biaryl tertiary amines promoted by t-BuOK/DMF. A reaction mechanism involving a-aminoalkyl radical intermediates is suggested. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Effects of weight cycling on body composition" and A.M. Prentice and colleagues in a 1992 issue.

Cranberry is an excellent source of dietary antioxidants. The present study investigated the effect of cranberry anthocyanin (CrA) extract on the lifespan of fruit flies with focus on its interaction with aging-related genes including superoxide dismutase (SOD), catalase (CAT), methuselah (MTH), insulin receptor (InR), target of rapamycin (TOR), hemipterus (Hep), and phosphoenolpyruvate carboxykinase (PEPCK). Results showed that diet containing 20 mg/mL CrA could significantly prolong the mean lifespan of fruit flies by 10% compared with the control diet. This was accompanied by up-regulation of SOD1 and down-regulation of MTH, InR, TOR and PEPCK. The stress resistance test demonstrated that CrA could reduce the mortality rate induced by H2O2 but not by paraquat. It was therefore concluded that the lifespan-prolonging activity of CrA was most likely mediated by modulating the genes of SOD1, MTH, InR, TOR and PEPCK. [ABSTRACT FROM AUTHOR]

Palmitic acid, one of the saturated free fatty acids, impairs cardiovascular function as manifested by inducing vascular inflammation, apoptosis and over-production of reactive oxygen species (ROS) although the origin for ROS remains unclear. The present study investigated the cellular mechanisms underlying palmitate-induced impairment of endothelial function. Ex vivo treatment in tissue culture with palmitate concentration-dependently attenuated acetylcholine-induced endothelium-dependent relaxations, up-regulated the expression of cyclooxygenase-2 (COX-2) and elevated superoxide formation in mouse aortic endothelial cells (MAECs) measured by dihydroethidium (DHE) staining and electron paramagnetic resonance (EPR) spectroscopy. Superoxide scavengers, COX-2 inhibitor and thromboxane prostanoid (TP) receptor antagonist, but not COX-1 inhibitor reversed the harmful effects of palmitate. Furthermore, palmitate impaired acetylcholine-induced relaxations and raised superoxide in en face endothelium of aortas only from COX-1−/− mice but not from COX-2−/− mice. Palmitate increased the production and release of TXB2, a stable thromboxane A2 metabolite in mouse aortas, which was abolished by COX-2 inhibitor. Superoxide scavenger did not affect palmitate-induced up-regulated expression of COX-2 in MAECs. Both real time PCR and luciferase reporter gene assay confirmed COX-2 up-regulation in palmitate-treated MAECs and NF-κB was substantially involved in this up-regulation. The present study provides novel evidence that palmitate up-regulates COX-2 through NF-κB-dependent mechanism and resultant COX-2-associated oxidative stress impairs endothelium-dependent relaxations in mouse aortas. [ABSTRACT FROM AUTHOR]

It has been shown that dietary phytosterols intake is inversely related to plasma total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) concentrations. The present study investigated effect of β-sitosterol intake frequency on plasma lipoprotein profile and the gene expression of transporters, receptors and enzymes involved in cholesterol metabolism. Thirty-three hamsters were divided into three groups with the control hamsters being gavage-administrated 3 mg cholesterol 3 times per day, whereas the second group being gavage-administered 3 mg β-sitosterol with 3 mg cholesterol 3 times per day (S-3) and the third group being gavage-administered 9 mg β-sitosterol with 3 mg cholesterol for one time and 3 mg cholesterol for the other two times per day (S-1). Results demonstrated that compared with the control group, hamsters gavage-fed β-sitosterol had a significant decrease in plasma TC and non-high density lipoprotein cholesterol (Non- HDL-C) concentration, but there was no significant difference between S-3 and S-1 groups. Real time PCR analysis revealed that the cholesterol-lowering activity of β-sitosterol was mediated by its inhibition on the intestinal cholesterol absorption with up- regulation of Niemann-Pick C1 like 1 (NPC1L1), ATP binding cassette transporters 5 and 8 (ABCG5/8) and microsomal triacylglycerol transport protein (MTP), but no significant difference was found between S-3 and S-1 groups. It was concluded that β-sitosterol was effective in reducing plasma cholesterol level and for a given dose of β-sitosterol, the administration frequency had no effect on plasma lipoprotein profiles. [ABSTRACT FROM AUTHOR]